With the development of technology, image processing is more and more widely used. Image scaling is an important part of the image processing. Image scaling requires that images be resized at a continuous ratio. The conventional method of image scaling is to calculate an image from its coordinate origin point by point, from left to right, and row after row, and so as to calculate the scaling result of the full image. In the scaling process, the conventional image scaling method often uses a product of the natural coordinates and numerator of a scale factor as the basis of weight calculation, which is computationally expensive and difficult to implement.